Arrangement for a touchscreen and related method of manufacture

ABSTRACT

Arrangement for use with a touchscreen, includes a substrate, such as an optically substantially transparent film or a film defining a through hole, the substrate including support electronics, such as printed electronics including a number of printed conductors, for providing power, control and/or communications connection to further electronic components, a number of emitters and detectors arranged on the substrate into contact with the support electronics, for emitting and detecting light, respectively, and a lightguide arranged onto the substrate such that the emitters and detectors, and optionally at least part of the support electronics, are substantially immersed in the lightguide material, the properties of the lightguide including the refractive index of the lightguide material being selected and the emitters and detectors being configured so as to enable, when in use, total internal reflection (TIR)-type propagation of light within the lightguide between the emitters and detectors and recognition of a touch on the basis of a drop in the TIR performance as determined from the detected light. A related method of manufacture is presented.

FIELD OF THE INVENTION

Generally the invention relates to optics and electronics. Particularly,however not exclusively, the invention pertains to UIs (user interface)comprising a touchscreen arrangement utilizing the total internalreflection (TIR) phenomenon.

BACKGROUND

Concerning contemporary and future electronic appliances for bothconsumer and professional use, the importance of a decent UI andusability in general cannot be stressed too much. In addition toconventional keypad, keyboard, or button arrangements, different kindsof touchscreens have been developed to provide the users of theappliances with more instant and versatile way of controlling therelated applications.

Touchscreens may apply of a number of varying technologies for obtainingthe touch-sensitive functionality. Among various other potential optionse.g. capacitive, resistive, infrared, optical imaging (camera-based),acoustic, and hybrid solutions are feasible.

Some infrared solutions implement an unrestricted optical connectionbetween light sources and receivers, whereupon a finger or stylusdeforming the screen cover, which overlays the display and light beamsof the detection arrangement, then interrupts one or some of the beamsfor location detection purposes, or alternatively, the finger or stylusmay directly interrupt the beam(s) in versions having no transparentoverlay plate.

Touch detection capability of an infrared solution may also rely on FTIR(frustrated total internal reflection) phenomenon, wherein the amountand distribution of light reaching the detectors is dependent on thedisturbance introduced to a lightguide surface by e.g. a fingertip or astylus applied for control input purposes so that a phenomenon called‘Frustrated Total Internal Reflection’ (FTIR), i.e. light (energy)leakage, takes place.

FIG. 1a illustrates the FTIR phenomenon in connection with a lightguide.In the scenario of sketch 102, a ray of light 104 is incoupled to thelightguide 106 at one end in such a way that it propagates inside thelightguide by totally reflecting 108 from the walls thereof. The ray 104finally exits the lightguide 106 via the far-end thereof. In thesubsequent scenario of sketch 110 a fingertip 112 is placed on thelightguide top surface so that at least part of light is absorbed (inthe finger), diffusively reflected, and/or refracted 114 at theparticular location of contact in different directions, e.g. outside thelightguide 106, and possibly only a portion of the original ray isspecularly reflected and ultimately reaches the far-end as earlier. Notethat the ray 104 is represented thinner in the figure after theinteraction point 114 in the original direction of propagation, which isused to depict the aforesaid effect of energy loss (the star and smallarrows in the figure) due to the FTIR taking place. FTIR-based lightleakage/loss may be then detected and utilized in position sensingapplications such as touchscreens that generally exploit the TIR effectof light.

Some theoretical aspects behind the (F)TIR phenomenon are next brieflyderived from the well-known Snell's law. Considering the standardrepresentation thereof, i.e. n₁ sin θ₁=n₂ sin θ₂, wherein n's representthe indexes of refraction on the both sides of a medium border wherebyθ's represent the incident angles relative to the normal of the mediumborder, respectively, and then setting θ₂, which thus refers to therefracted ray, as 90°, we obtain a so-called ‘critical angle’ for theincident angle θ₁ via the modified equation of Snell's: n₁ sin θ₁=n₂.Typically, when light enters a boundary region between two media,portion thereof is refracted and portion is reflected. However, for theangles of incidence larger than the critical angle, the light will besubstantially completely reflected at the medium border, wherein theangle of incidence is equal to the angle of reflection according to thelaw of reflection. A general prerequisite for the total internalreflection to occur is the propagation direction of light from themedium with a higher index of refraction (optically denser material)into the medium with a lower (˜less dense material) index, i.e. n₁>n₂.

For instance, in the example of FIG. 1a placing a finger on thelightguide may change the refractive index of the neighbouring mediumradically (assuming the original neighbouring medium 2 is e.g. air withrefractive index of about 1 meanwhile the index of a human skin may beabout 1.4-1.5, for instance) potentially causing the considerablecoupling loss between the lightguide incoupling and out-coupling endsdue to the increase in the critical angle and possibly even therequisite for total internal reflection n₁>n₂ not holding true anymore,whereupon many rays falling between the range of old and new criticalangles may now actually refract instead of reflection. In practice, e.g.the surface roughness of the lightguide affects the fact that thesealing between it and the finger, which has surface irregularities aswell, is not perfect, i.e. some air still remains in between. However,thanks to a so-called evanescent wave coupling, wherein evanescent wavesextending from the lightguide across the lightguide-external mediumborder (e.g. glass-air interface) to a further nearby (order of lightwavelength) medium, such as the human finger, having a higher refractiveindex compared to the sandwiched medium, such as air, and pass energythereto as well like in quantum tunneling, a perfect seal is not evenrequired for coupling purposes. Thus, the total internal reflection issaid to be ‘frustrated’.

Publication US20060114237 discloses an FTIR touch screen provided withinfrared emitters/receivers. The concept of the solution of publicationis visualized in FIG. 1b as an isometric sketch. The disclosedarrangement utilizes a strobing-type scan, wherein a plurality of lightemitters 120, 122 and receivers 118, 124 have been organized along theedges of the lightguide 106 and they are sequentiallyactivated/deactivated in emitter-receiver pairs (˜note the broken linesillustrating the main direction of light propagation between an emitterand receiver of a single pair) so that a touch at a certain location onthe lightguide can be detected by the reduced amount of light at thereceiver of an active emitter-receiver pair due to the FTIR phenomenon.

Without any intention to deny the advantages and benefits offered bycurrently available touchscreen or corresponding solutions in providingmore sophisticated UI means over more conventional options such askeyboards and mouses, certain problems still exist therewith naturallydepending on each particular use case. For example, traditionaltouchscreens are often somewhat pricey to implement and manufacture, andthey also take a considerable amount of space in the end product withoutforgetting the induced additional weight, which must be thus taken intoaccount in the very beginning of the overall R&D project. Thetouchscreens may even consume surprising amount of extra power e.g. inthe context of mobile devices. Further, additional structures such aslight incoupling and/or outcoupling structures, e.g. prisms, reflectors,gratings, etc, may be required to funnel the light from the light sourceto the lightguide and/or from the lightguide to the receiver,respectively. Such structures require some more design work and may addto the end product weight, coupling losses, and price among otherfactors.

SUMMARY OF THE INVENTION

The objective of the embodiments of the present invention is to at leastalleviate one or more of the aforesaid drawbacks evident in the priorart arrangements in the context of touchscreens utilizing the TIRphenomenon including e.g. various FTIR-based touchscreen applications.The objective is achieved with a touchscreen arrangement, such as amold-on-film FTIR touchscreen arrangement, wherein the lightguide may beover-moulded onto the substrate comprising the necessary electronicsincluding different optoelectronic components.

Thereby, in accordance with one aspect of the present invention anarrangement for a touchscreen comprises:

a substrate, such as an optically substantially transparent film, saidsubstrate comprising support electronics, such as roll-to-roll processedprinted electronics including a number of printed conductors, forproviding power, control and/or communications connection to furtherelectronic components,

a number of emitters and detectors arranged on said substrate intocontact with the support electronics, for emitting and detecting light,respectively, and

a lightguide arranged onto the substrate such that said emitters anddetectors, and optionally at least part of said support electronics, aresubstantially immersed in the lightguide material, the properties of thelightguide including the refractive index of the lightguide materialbeing selected and the emitters and detectors being configured so as toenable, when in use, total internal reflection (TIR)-type propagation oflight within the lightguide between the emitters and detectors, andrecognition of a touch on the basis of a drop in the TIR performance asdetermined from the detected light.

In one embodiment at least part of the above arrangement is configuredto act as an overlay for a display such that the display view can beseen by the user of the display by looking through the (part of the)arrangement, e.g. a touch area part or ‘window’ portion thereof, withina predetermined range of viewing angles. The arrangement may be thuspositioned over a display for providing a touch interface. Thearrangement may further be integrated with the display structure suchthat these two (touch area of the lightguide/underlying substrateportion and the display) are substantially in physical contact.Alternatively, they may physically separate, i.e. having e.g. air inbetween, as long as the functional connection is still provided.

Therefore, in a preferred embodiment, the substrate, such as a flexfilm, is optically substantially transparent so that a display or otherlight source/reflector may provide light through it towards the user.The required degree of transparency depends on the particular use case.In one embodiment the preferred transmittance in relation topredetermined wavelengths of light (e.g. infrared) may thus residewithin the range of about 80 to 95%, for instance. In alternativeembodiment the substrate is translucent so that is passes lightdiffusively. In a further alternative, the substrate might even besubstantially opaque, whereupon the arrangement of the present inventionis not suitable for passing light through but may be still be suitableand used as a control (touch) input means for various other purposeslike the touchpads of the portable computers, for example. Yet in oneembodiment, a portion of the substrate, such as the center portion, maybe provided with an opening, which may substantially define a throughhole, so that e.g. the display light can propagate through it and thelightguide material. Accordingly, the substrate may in this case beeither transparent, translucent, or opaque, which applies also toscenarios wherein the arrangement is to be implemented as a displayoverlay.

In the above or another embodiment, the touch screen arrangement of thepresent invention may be obtained by injection moulding, wherein thesubstrate, e.g. the flex film, provided with electronics thereon, saidelectronics including the support electronics and further electroniccomponents like the optoelectronic emitters and detectors, is used as aninsert in the injection moulding process during which the lightguidematerial is over-moulded onto the electronics and the related substratesurface. Advantageously one or more coupling entities, such asconnectors or contacts, which may have been already provided on thesubstrate to connect the arrangement to external elements, such as amain board of the host device, are not completely over-moulded, or areat least cleared afterwards. Also other methods for producing thelightguide and/or additional layers, such as lamination, may be appliedin addition to or instead of (over-)moulding.

The arrangement may naturally further comprise one or more additionalemitters and/or detectors not immersed in the lightguide material, butbeing still optically optionally coupled thereto.

In supplementary or alternative embodiment, the lightguide material maybe heterogeneous and comprise several sub-portions, or “sub-blocks”, ofdifferent materials arranged such that the various sub-portions arejoined together or at least located next to each other so as to form theoverall lightguide. For instance, the portion(s) wherein at least oneemitter and/or detector are immersed may comprise material differentfrom the one or more remaining lightguide portion(s).

In the above or some other embodiments, at least portion of the supportelectronics, such as conductors, may include printed electronics.

Likewise, in the above or some other embodiments at least portion of theremaining electronics, such as the emitters, detectors, and/or othercomponents and elements, may be printed on the substrate by utilizing aselected printing technique, or attached as ready-made entities, e.g.SMT (surface-mount technology) and/or flip chip entities, to thesubstrate by e.g. glue or other adhesive.

In various embodiments of the present invention the touch action mayrefer to placing an actuation element such as a finger or a stylussubstantially into connection with the lightguide, i.e. the lightguideitself or the outmost additional material layer, if any, thereon. Theconnection may include, depending on each particular embodiment and e.g.the associated sensitivity of the detectors, a close-range connectionvia mere evanescent coupling, or a true physical contact, or acombination thereof, for example.

In the above or other embodiments, the arrangement may be calibratedsuch that in order to register the contact as an actual “touch” theusers of the touchscreen arrangement according to the present inventionhave to physically contact the overlay surface, i.e. not just rely onevanescent coupling, either by a finger or a stylus so that the touch isdeemed as recognized from a drop in TIR performance is clearlydetectable in order to avoid annoying false detections etc.

The touch is typically initiated for control input purposes, such astriggering an action, at a target device that is at least functionallycoupled to the touchscreen arrangement.

One or more properties, such as the refractive index, of the lightguideare preferably selected and/or designed to act co-operatively with apredetermined external medium, such as air, or a range of predeterminedmedia optionally including air, to provide the TIR effect for theincoupled light. Instead of air, the adjacent external medium mayinclude e.g. a material layer provided on one or more, e.g. top andbottom or all (when in use) side faces of the lightguide. The materiallayer may be arranged thin enough to enable evanescent coupling throughit to the actuation element and thus touch detection via an FTIR effect,while the TIR effect may already take place at the lightguide-materiallayer interface. In another embodiment, one or more optical propertiesof the material layer and the lightguide, such as the refractiveindexes, are selected about the same so that the light propagatingwithin the lightguide under TIR condition does not substantially reactto the interface and the TIR takes place at the material layer-furtherexternal medium (e.g. air) interface. The material layer may beconfigured to enhance the touch feel or improve/lower the actuationelement's slide, e.g. by friction adjustment, on the lightguide's touchsurface, for example. The material layer may alternatively oradditionally act as a protective layer against physical or chemicalimpulses. There may be a plurality of (different) material layers on thesurfaces of the lightguide as long as the TIR and FTIR effects can stillbe effectuated. In one embodiment the lightguide material is selecteddurable enough to act as a screen cover for the underlying displayelement.

In one either supplementary or alternative embodiment a multi-layersolution may be utilized such that by locally touching and thus, forexample, deforming an upper, e.g. protective, layer by a finger orstylus, or other suitable means, the underlying lightguide layer portionalso deforms (the touch can be considered as funneled thereto) and theassociated TIR performance drops e.g. due to the energy leakage at theboundary of the lightguide and the adjacent layer, which may be appliedfor recognizing a touch. There may be one or more additional layerspositioned between the topmost contact layer of the multi-layerstructure and the lightguide. The additional layers may convey the forcetargeted to the topmost layer towards the lightguide and deform as well.Alternatively, the lightguide layer may be directly contacted by thefinger or stylus and deformed therewith.

The properties of the substrate (a thin film or a thicker substrate ofplastics or some other material) may be selected such that the lightbehaves in a predetermined, desired manner at the lightguide-substrateinterface. In one embodiment one or more optical properties of thesubstrate and the lightguide, such as the refractive indexes, areselected about the same so that the light propagating within thelightguide under TIR condition does not substantially react to theinterface. In another embodiment, said one or more optical properties ofthe substrate and lightguide, e.g. the refractive index, are selectedsuch that the TIR-propagating light is reflected, preferably as much aspossible, from the lightguide-substrate interface. In any case, when thetouchscreen overlay of the touch screen arrangement is disposed over adisplay, which is indeed a typical use scenario, the substrate shall beselected so as to remain optically transparent to the light, i.e.transparent to the (wavelengths of) visible light that is used toilluminate the displayed details to the user through the arrangement.

The detection levels for recognizing a sufficient drop in the TIRperformance, which indicates a deliberate touch, may be determined bytesting the response and/or change thereof at the detector a) when theemitter is constantly on and b) when a predetermined actuation elementor range of elements, such as a fingertip (skin), is brought intocontact, or at least within the range of evanescent coupling, with thelightguide. The detection threshold may be fixed or adaptive. In oneembodiment the adaptive threshold analyzer determines the change in thedetected intensity of light relative to an adaptive basic intensitylevel, instead of absolute values, for recognizing a touch. The basiclevel may be measured with a longer time window either constantly or ina timed manner, e.g. at intervals.

The emitters may include optoelectronic components such as LEDs (lightemitting diode) or OLEDs (organic LED), for example.

The detectors may include optoelectronic components such as photodiodesor phototransistors, for example. In addition or alternatively, imagesensors such as CCD (charge coupled device), MOS (metal-oxidesemiconductor), or other types of sensors may be applied.

The lightguide material may include e.g. PC (polycarbonate), PMMA(polymethyl methacrylate). PA (polyamide, nylon), COC (cyclo olefincopolymer), and/or COP (cyclo olefin polymer).

The substrate material may include e.g. PET (polyethyleneterephthalate), PC, PEN (polyethylene naphthalate), PI (polyimide), LCP(liquid crystal polymer), PE (polyethylene), and/or PP (polypropylene).

The number of emitters and detectors may be, but does not have to be,equal. In one embodiment the emitters and detectors are organized inpairs, whereupon one pair may, in one activation option, be arranged tobe active at a time. In a minimum case, there is a single emitter anddetector arranged on the substrate.

In another aspect of the present invention, a method for manufacturing atouch-screen arrangement comprises:

providing a substrate, such as an optically substantially transparentfilm,

arranging support electronics, such as printed electronics including anumber of printed conductors, on the substrate for providing power,control and/or communications connection to further electroniccomponents,

arranging a number of emitters and detectors on said substrate intocontact with the support electronics, for emitting and detecting light,respectively, and

producing a lightguide onto the substrate such that said emitters anddetectors, and optionally at least part of the support electronics, aresubstantially immersed in the lightguide material, the properties of thelightguide including the refractive index of the lightguide materialbeing selected and the emitters and detectors being configured so as toenable, when in use, total internal reflection (TIR)-type propagation oflight within the lightguide between the emitters and detectors andrecognition of a touch on the basis of a drop in the TIR performance asdetermined from the detected light.

As alluded hereinbefore, the utility of the different aspects of thepresent invention arises from a plurality of issues depending on eachparticular embodiment. The manufacturing costs for producing the touchscreen arrangement in accordance with the present invention may be keptlow due to rather extensive use of affordable and easily obtainablematerials, components, and process technology. The feasible processtechnology also enables rapid industrial scale manufacturing of thearrangement in addition to mere prototyping scenarios. The arrangementmay be kept thin, light, and energy conserving in order to suit most usescenarios with little modifications to the surrounding elements anddesigns. The coupling losses between the emitters, lightguide, and thedetectors may be minimized as external, typically lossy, light funnelingmeans such as gratings etc. are not necessary. The touch detectioncapability of the various embodiments of the arrangement is good withlow sensitivity to e.g. dirt on the touch surface, and even multi-touchapplications may be constructed. The arrangement may be easily combinedwith an existing display or device layout, and conveniently connected toan external target entity such as a host device mainboard via a flexcable, for example, which also enables easy replacement thereof in thefuture. The arrangement may further be made robust towards externalimpacts, depending on the used materials, in which case the arrangementalso function as an optionally replaceable screen cover for theunderlying display element. Yet, the arrangement suits particularly wellvarious industrial applications including e.g. industrialautomation/electronics control apparatuses, as it may provide hermetical(˜splash-proof) isolation from the hostile use environment like humidand/or dusty air. The embodiments of the invention may be utilized invarious hand-held devices, wristop devices, gaming devices, householdappliances, sports devices, and automotive products, for instance.

The expression “a number of” may herein refer to any positive integerstarting from one (1). The expression “a plurality of” may refer to anypositive integer starting from two (2), respectively.

The terms “immerse” and “embed” are used herein interchangeably.

In one embodiment described in more detail hereinafter, a touch screenarrangement following the basic principles set forth hereinbefore isprovided with various alternative features disclosed as well.

Different embodiments of the present invention are also disclosed in theattached dependent claims.

BRIEF DESCRIPTION OF THE RELATED DRAWINGS

Next, the embodiments of the present invention are more closely reviewedwith reference to the attached drawings, wherein

FIG. 1a illustrates the total internal reflection phenomenon andutilization thereof in touchscreens;

FIG. 1b illustrates one prior art touchscreen arrangement with multipleemitters and detectors disposed along the sides of a lightguide.

FIG. 2a illustrates one embodiment of the present invention.

FIG. 2b illustrates an exemplary cross-section along the line A-A of theembodiment type shown in FIG. 2 a.

FIG. 2c illustrates another embodiment of the present invention whereinthe substrate defines a frame with an opening in the center thereof.

FIG. 3a generally illustrates one embodiment for manufacturing thetouchscreen arrangement of the present invention.

FIG. 3b is a flow diagram of an embodiment for manufacturing thetouchscreen arrangement of the present invention.

FIG. 4 illustrates top and bottom views of one embodiment of thetouchscreen arrangement in accordance with the present invention.

FIG. 5a is a block diagram of one embodiment of an apparatus comprisingthe touchscreen arrangement in accordance with the present invention.

FIG. 5b is a block diagram of one embodiment of the touchscreenarrangement according to the present invention.

FIG. 6 shows timing diagrams for two embodiments of sequentially drivingthe emitters and detectors of the touchscreen arrangement in accordancewith the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS. 1a and 1b were already contemplated hereinbefore in connectionwith the review of the background of the invention.

Now referring to FIG. 2a , a perspective view 202 of one embodiment ofthe touch-screen arrangement is sketched. The touchscreen arrangement,which may be implemented as an overlay for a display, comprises asubstrate such as a (flexible) film 206 accommodating electronics 204such as support electronics like conductors and/or control circuitry,and also further electronic elements such as optoelectronic lightemitter(s), detector(s), and optionally other components. The lightguide208 has been provided thereon.

For example, in-mould integration may be applied such that thelightguide material is over-moulded onto the electronics on thesubstrate, wherein the substrate provided with the electronics is usedas an in-mould insert in the injection moulding process. As a result,the over-moulded material acts as a lightguide between the emitters andthe detectors and provides sealing/encapsulation to other underlyingelements as well.

The dimensions X, Y, Z of the arrangement may be selected so as to fiteach particular manufacturing and use scenario (e.g. host device anddisplay layout) as well as possible. For example, the substrate sizecould be about 150 mm (X)×150 (Y) mm×125 μm (Z) wherefrom a smallerdedicated portion may be further determined for the over-moulding, ifdesired. The thickness (Z) of the substrate may naturally vary dependingon the embodiment and reside e.g. within the range of about 50 to 500μm, for example. The thickness of the lightguide 208 may also vary usecase—specifically and be about 1 mm-10 mm, for example. <=1 mm thicknessmay be desirable in applications wherein detection sensitivity andresponse is preferred over stiffness. On the contrary, thicknesses over5 mm may fit particularly well scenarios wherein stiffness andassociated additional durability is required. The intermediatethicknesses 1.5-2 mm may also suit many applications, e.g. mobileterminals and PDAs.

The shape of the arrangement and its constituents, e.g. the lightguide208 and substrate 206, may be defined on the basis of the usedmanufacturing method and desired target shape(s). The illustrated,however merely exemplary, arrangement has substantially a rectangular(cuboid) shape, which works particularly well e.g. with roll-to-rollmanufacturing methods and with typical display applications, but alsoe.g. round(ed) shapes are possible and achievable via proper cutting,for instance. Still in the illustrated example, the edges parallel tothe Y-axis have been slightly bent downwards, in use position, to betterfit the target apparatus, which could be a mobile terminal, a PDA(personal digital assistant), a music player, a multimedia player, or anindustrial electronics and/or automation device, for example.

FIG. 2b discloses an exemplary cross-section along the line A-A of theembodiment type shown in FIG. 2a . In this example the lightguide 208covers most of the substrate 206 surface onto which the electronics 204including the emitters/detectors 210 and support electronics 212 havebeen provided. However, not all the electronics 204 have to reside asencapsulated by the lightguide 208. This fact is visualized by a singleelectronic component 204 and a conductor portion on the right from thelightguide 208, wherein the conductor is illustrated by a thickerhorizontal line extending along the border line between the substrate206 and the light-guide 208. The electronics 204 may comprise elementsof different dimensions as illustrated in the figure by varying heightand width of the cross-sections.

In one embodiment the emitters and detectors 210 are located near theborder of the lightguide 208, being preferably positioned such that thelight is propagated substantially through the whole length of thelightguide in a predetermined direction after output by an emitter andprior to being captured by a detector. For instance, two rows ofemitters may be located parallel and close to the two neighbouring sidefaces of the lightguide, respectively, e.g. two neighbouring side facesbeing parallel to planes YZ and XZ in FIG. 1, and two rows of detectorsbe similarly located relative to the opposite neighbouring side faces sothat the light emitted by a predetermined emitter is captured by one ormore predetermined detectors near the opposite side face. In otherembodiments, at least some of the emitters and/or detectors 210 may bepositioned otherwise. For example, they 210 may be located radially suchthat the detector formation has a certain first radius (distance) from apredetermined center point or line, whereas the emitters have another,second radius relative to the same reference. In the case of angularlightguide, the detectors/emitters 210 may also be located near thevertices (˜corner points) thereof.

FIG. 2c discloses an embodiment wherein a portion 214 of the substrate206, in this example specifically the center portion, is provided with athrough hole. Thereby e.g. display light can propagate via it and thenpass through the lightguide material 208 towards the user. Accordingly,the substrate 206 may in this case be either transparent, translucent,or opaque, which applies also to scenarios wherein the arrangement is tobe implemented as a display overlay.

FIG. 3a depicts, in a very general sense, one embodiment formanufacturing the touchscreen arrangement of the present invention. Inphase 302 the substrate is provided with the necessary electronics suchas conductors, detectors, emitters, and necessary control circuitry,which is illustrated by a rotating arm or nozzle working on thesubstrate surface. The arm could belong to a flip-chip bonding apparatusor inkjet printer, for example. In phase 304 the lightguide is arrangedonto the substrate/electronics aggregate so that at least part of theelectronics are embedded in the lightguide that thus encapsulates theaforementioned part, which may be seen in phase 306 representing oneembodiment of the touchscreen arrangement capable of being used e.g. asa display overlay. The overlay may be ready-fitted to a host device(housing) or provided upon the display thereof and functionally coupledthereto only when needed.

FIG. 3b is a more detailed flow diagram of one embodiment formanufacturing the touchscreen arrangement of the present invention.

At 308, referring to a start-up phase, the necessary tasks such asmaterial, component and device selection and acquisition take place. Indetermining the emitter and sensor types or e.g. other electronics andsubstrate/lightguide/conductor materials and shapes, specific care mustbe taken that the individual elements and material selections worktogether and survive the selected manufacturing process of the overallarrangement, which is naturally preferably checked up-front on the basisof the manufacturing process vs. component data sheets, or by analyzingthe produced prototypes, for example.

The reference numeral 322 generally refers to manufacturing phasesduring which the substrate is provided with electronics comprising boththe support electronics for driving the optoelectronic elements etc. andthe actual optoelectronic elements. The internal phases 310 and 312 maybe executed in a varying order that best fits the particular usescenario in question. Further, the internal tasks of shown phases may bereallocated between the phases 310, 312, if considered advantageous.

The used substrate may include, for example, polymers such as a PET orPC film. An applicable substrate shall be generally selected such thatthe desired flexibility, robustness, and other requirements likeadhesion properties in view of the electronics and the lightguidematerial, or e.g. in view of available manufacturing techniques, aremet.

The selected substrate may also be preconditioned prior to and/or duringthe illustrated processing phases. The substrate may be preconditionedto increase adhesion with other materials such as injection-mouldedlightguide plastics, for example.

In 310 the support electronics, such as electrical conductors andcircuitry, may be printed or otherwise formed onto the substrate, on oneor more (e.g. predetermined top and/or bottom, when in use) side faces.Feasible techniques for providing the electronics generally includescreen printing, rotary screen printing, gravure printing, flexography,ink-jet printing, tampo printing, etching (like with PWB-substrates),transfer-laminating, thin-film deposition, etc.

For instance, in the context of conductive pastes, silver-based PTF(Polymer Thick Film) paste could be utilized for screen printing thecircuit design on the substrate. Also e.g. copper or carbon-based PTFpastes may be used. Alternatively, copper/aluminum layers may beobtained by etching. In a further alternative, conductive LTCC (lowtemperature co-fired ceramic) or HTCC (high temperature co-firedceramic) pastes may be sintered onto the substrate. One shall take intoaccount the properties of the substrate when selecting the material forconductors. For example, sintering temperature of LTCC pastes may beabout 850 to 900° C., which may require using ceramic substrates.Further, silver/gold-based nanoparticle inks could be used for producingthe conductors.

Reverting to the feasible printing techniques, the paste/ink shall beselected in connection with the printing technique and the substratematerial because different printing techniques require differentrheological properties from the used ink/paste, for instance. Further,different printing technologies provide varying amounts of ink/paste pertime unit, which often affects the achievable conductivity figures.

Electronic SMT components and circuits or (flip) chips may be attachedto the substrate by adhesive, such as an epoxy adhesive, for example.Both conductive (for enabling electrical contact) and non-conductive(for mere fixing) adhesives may be utilized. Such elements arepreferably selected so as to withstand the pressure and temperature ofthe utilized lightguide-establishing process such as the injectionover-moulding process.

In 312 the optoelectronic elements including the light emitter(s) anddetector(s) are bonded with the substrate by adhesive, for example.Accordingly, suitable printing technologies may be exploited. E.g. OLEDsmay be printed on the substrate by an inkjet printer or other applicabledevice.

A person skilled in the art will appreciate the fact that provision ofoptoelectronic and other electrical elements on the substrate may invarious other embodiments of the present invention split alsodifferently, if at all, between the illustrated and merely exemplarystages 310 and 312, and the related number of production stages may beadapted accordingly. For example, most of the components, including boththe support components and the optoelectronic components, may be addedto the already formed circuit model of mere conductors substantiallyduring the same production stage or in multiple subsequent stages.

The use of flexible materials preferably enables carrying out at leastsome of the items 322, 310, 312, or further items, by roll-to-rollmethods, which may provide additional benefits time-, cost- and evenspace-wise considering e.g. transportation and storage. In roll-to-roll,or ‘reel-to-reel’, methods the desired elements, such as optical and/orelectrical ones, may be deposited on a continuous ‘roll’ substrate,which may be both long and wide, advancing either in constant or dynamicspeed from a source roll, or a plurality of source rolls, to adestination roll during the procedure. Thus the substrate may thuscomprise multiple products that are to be cut separate later. Theroll-to-roll manufacturing advantageously enables rapid and costeffective manufacturing of products also in accordance with the presentinvention. During the roll-to-roll process several material layers maybe joined together ‘on the fly’, and the aforesaid elements such aselectronics may be structured on them prior to, upon, or after theactual joining instant. The source layers and the resulting band-likeaggregate entity may be further subjected to various treatments duringthe process. Layer thicknesses (thinner layers such as ‘films’ aregenerally preferred in facilitating roll-to-roll processing) andoptionally also other properties should be selected so as to enableroll-to-roll processing to a preferred extent.

In 314 the lightguide is formed on the substrate such that at leastportion of the electronics is immersed therein. Thereby, the lightguidemay act as a cover for the electronics and as a light-transporting (TIR)medium between the emitter(s) and the detector(s).

In one embodiment the lightguide comprises plastic material such as PCthat is over-moulded onto the substrate like a thermoplastic polymerfilm, e.g. a PET film, having electronics already provided thereon. Thesubstrate may be applied as an insert into the mold of the injectionmoulding apparatus so that the PET is cast upon the substrate. Thelightguide material and the used attachment method shall be preferablyselected such that the electronics on the substrate remain unharmedduring the process, while the lightguide material is properly attachedto the substrate and the optical properties thereof are as desired.

In 316 and 320 it is optionally checked whether further processing ofthe lightguide-substrate aggregate is required, and if this is the case,the necessary steps are taken, respectively. For example, supplementarymaterial layers may be added to the touchscreen arrangement. In oneembodiment, at least part of the arrangement, such as (a portion of) thelightguide, may be provided with a hard-coating that protects againstscratches. Additionally or alternatively, other functional or decorativelayers or treatments may be provided, such as a layer for enhancing thefeel of the touch surface from the standpoint of the user. Further, step318 may refer to coupling additional and/or external elements such asconnectors or (flex) cables to the arrangement, and even to placing thearrangement in the target product such as a mobile terminal or a controldisplay. Yet, different quality checks and tests concerning thefunctioning of the over-moulded elements, the lightguide and/orremaining entities may be performed.

It is to be understood that phase 316 may not necessarily refer to areal-time check e.g. on the basis of a real-time monitored property ofthe arrangement such as the functioning of the electronics orlightguide, as the ‘check’ may also refer to a predetermined processcontrol parameter value (e.g. add hard-coating=TRUE) coded in theprocess control data, which is then used to define the treatment wheretothe arrangement is subjected.

In phase 318 the method execution ends and the obtained touchscreenarrangement(s) may be transported forward.

FIG. 4 illustrates top and bottom views of one embodiment of thetouchscreen arrangement's layout outline in accordance with the presentinvention. In item 402 a ‘top’ view is shown and in item 404 a bottomview is shown. The conductors, connectors, chips, and other componentsare recognizable in the figure, wherein the emitter/detector arrayssurround a rectangular, substantially a square, touch screen window tobe used as a touch area overlay for a display, for example.

FIG. 5a is a general block diagram of one embodiment of an apparatus 501comprising the touchscreen arrangement in accordance with the presentinvention. The apparatus may include or be a mobile terminal, a PDA, acontrol device for industrial applications, a multi-purpose computer(desktop/laptop/palmtop), etc. As being clear to a skilled person,various elements of the apparatus 501 may be directly integrated in thesame housing or provided at least with functional connectivity, e.g.wired or wireless connectivity, with each other. For instance, a display514 and the associated touchscreen 502 may be incorporated in theapparatus 501 as integrated or separate elements.

One potential, if not elementary, functional element that is included inthe apparatus is memory 506, which may be divided between one or morephysical memory chips and/or cards, may comprise necessary code, e.g. ina form of a computer program/application, for enabling the control andoperation of the apparatus, and further comprise other data, e.g.current settings and user data. The memory 506 may include e.g. ROM(read only memory) or RAM-type (random access memory) implementations.The memory 506 may further refer to an advantageously detachable memorycard/stick, a floppy disc, an optical disc, such as a CD-ROM, or afixed/removable hard drive.

A processing means 504, e.g. a processing/controlling unit such as amicroprocessor, a DSP (digital signal processor), a micro-controller orprogrammable logic chip(s), optionally comprising a plurality ofco-operating or parallel (sub-)units, may be needed for the actualexecution of the application code that may be stored in memory 506.Display 514 and keyboard/keypad 512 or other supplementary control inputmeans, such as keys, buttons, knobs, voice control interface, sliders,rocker switches, etc, may provide the user of the apparatus 501 withdata visualization means and control input means in addition to thetouchscreen 502 (˜user interface, UI) in connection with the display514. The processor 504 may control the touch-screen arrangement, or aspecific control means may be alternatively or additionally provided forthe purpose. Data interface 508, e.g. a wireless transceiver (GSM(Global System for Mobile Communications), UMTS (Universal MobileTelecommunications System), WLAN (Wireless Local Area Network),Bluetooth, infrared, etc), and/or an interface for a fixed/wiredconnection, such as an USB (Universal Serial Bus) port, a LAN (e.g.Ethernet) interface, or Firewire-compliant (e.g. IEEE 1394) interface,is typically required for communication with other devices. Theapparatus may include various supplementary elements 510 that can beused with the touchscreen arrangement 502, for instance. It isself-evident that further functionalities may be added to the apparatusand the aforesaid functionalities may be modified depending on eachparticular embodiment.

FIG. 5b is a block diagram of one embodiment of the touchscreenarrangement 502 according to the present invention. The touchscreenarrangement may in practice include own, external, and/or shared controlor other means, such as processor 524, in view of the rest of theapparatus 501 or a similar host system. For example, the processor 504could control also the touchscreen 502, i.e. processor 504=524, ifprovided with necessary connection to the support electronics of thelight-guide/substrate arrangement.

The arrangement 502 may comprise a controller switch, e.g. a‘demultiplexer’, 516 that drives the emitters of the actual touch screenoverlay 522, i.e. the functional part comprising a predetermined touchsurface (area) and the emitter/detector arrays or other patterns, and iscontrolled by processor 524, which may additionally or alternativelyrefer to a shared unit 504 controlling also other functions of theapparatus 501 as deliberated above. The provided control is illustratedas LED SELector and LED DRiVer signals. Also the detectors may becontrolled by the processor 524 or some other processing means e.g. viaa multiplexer switch 518. The provided control is illustrated asDETECTOR SELECT signal. The obtained detector signal(s) such as theillustrated SIGNAL DATA signal may be preprocessed such as amplified,filtered, and/or A/D-converted 520 prior to forwarding to the processor524 or some other processing means like processor 504. The illustratedfunctional elements may comprise further connections, e.g. viaconnectors or conductors possibly including data cables, to elementsthat are external to the touch screen arrangement or implemented on thesame substrate. One such connection has been illustrated as POSITION OUTin the figure.

A person skilled in the art will appreciate that the functionalities ofthe visualized blocks in FIGS. 5a and 5b may be in practicalcircumstances split differently between the shown and/or other entitiesdepending on the embodiment.

FIG. 6 depicts few merely exemplary timing diagrams of two embodimentsfor sequentially driving the emitters and detectors of the touchscreenarrangement. In the example marked with a reference numeral 602 a LED,or other type of an emitter, and a corresponding detector, such as aphototransistor or photodiode, are active substantially simultaneouslyas visualized by the control signals' up and down portions. Theemitter/detector pairs are sequentially activated in a continuous mannersuch that only one pair is active at a time. This is done for detectingand locating the touches.

As a concretized example, a channel may be defined as anemitter-detector-pair in X- or Y-direction, wherein X and Y define twoorthogonal axes, each of which being parallel with two borderlines of arectangular touch surface area (˜window) 606 surrounded by the emittersand detectors. Signal on a certain, location-dependent channel is thenbased on the intensity level of light emitted by a certain emitter anddetected at a corresponding detector. In the illustrated there are threeemitters and detectors disposed parallel to the X and Y axes on theopposite sides of the touch surface area 606, which is illustrated viathe vertical and horizontal broken lines denoting ‘channels’ across thelightguide surface, respectively.

By keeping all the emitters and detectors constantly on and given atouch on an area associated with the certain channel, which links to acertain touch surface ‘strip’ extending between the certain emitter andthe corresponding detector on the light-guide's overall touch area, thedetector still captures exceedingly lot of light from other activeemitters, which naturally reduces the touch recognition and localizationcapability and sensitivity of the arrangement. Thus, the emitters shallbe preferably pulsed on a channel-by-channel basis:

Turn on the LED X1 for a time tp, and read the signal at sensor X1simultaneously

apply latency for a time period tl, if needed

Turn on the LED X2 for a time tp, and read the signal at sensor X2simultaneously

apply latency for a time period tl if needed

. . .

Turn on the LED Y1 for a time tp, and read the signal at sensor Y1simultaneously

. . .

If decisive signal attenuation is detected relative to a channelcrossing (Xt, Yt), the touch location on the lightguide can beprogrammatically mapped to a corresponding point on the related display.Also, multiple crossings can be mapped to discrete multiple simultaneoustouches or a touch by a large finger or stylus.

Typical rise/fall times of optoelectronic components may be of the orderof few microseconds. Thus, the pulse times less than about 0.5 ms areeasily attained in terms of hardware. In a tested example set-up (12channels), the overall time for one whole sequence could be pushed toless than about 0.01 s. This is fast enough for most applications.

In the example marked with a reference numeral 604, ‘cross-talk’sequencing is used wherein one LED is associated with a plurality of, inthis example three, detectors, i.e. the one that is actually opposingthe LED, i.e. the ‘main’ detector, and the two adjacent ones. During thesequencing and active portion of a certain emitter, the detectionsignals of the associated three detectors may be then sequentially readas shown prior to moving into a next group of an emitter and threedetectors. Some detectors may be associated with a plurality ofemitters, i.e. the groups overlap relative to the detectors. By thisprocedure, the obtained resolution can be doubled in both directions(X/Y) at least on areas near the screen center because both temporal andpositional distribution of light as captured by detectors (localtemporal intensity level at each detector of the group) is available foranalysis. Further group configurations (e.g. multiple emitters—multipledetectors per group) are also possible.

In addition to touch recognition and localization aspects, touchintensity or pressure, i.e. how hard the finger or stylus is pressedupon the lightguide, may be monitored for additional control of thetarget device. The pressure may be deduced from the amount andoptionally nature of the FTIR-based light intensity loss (i.e. moreFTIR-induced loss indicates more touch pressure) at a detector, forexample.

Considering the present invention in light of the related processparameters and set-up, few further guidelines can be given on the basisof conducted tests. When the substrate is PET and the lightguideplastics to be over-moulded thereon is PC, the temperature of the meltedPC may be about 280 to 320° C. and mould temperature about 20 to 95° C.,e.g. about 80° C. The used substrate (film) and the process parametersshall be selected such that the substrate does not melt and remainssubstantially solid during the process. The substrate shall bepositioned in the mould such that it remains properly fixed. Likewise,the preinstalled electronics shall be attached to the substrate suchthat they remain static during the molding.

In some embodiments, the zero-order path (direct path withoutreflections) between a light emitter and a corresponding light detectormay be blocked, in addition to or instead of using certainemitter/detector alignment for the same purpose, by a specific blockingstructure, such as a mask, in order to increase the relative proportionof the TIR-propagated light at the detector, which may furtherfacilitate detecting the FTIR-based loss, whenever the TIR-phenomenon onthe lightguide surface (or associated coating surface) is disturbed bythe touch of a finger(tip) or other stylus.

Correspondingly, the detector(s) may be protected from external unwantedlight (e.g. sunlight or display lighting) by a blocking structure.

The scope of the invention is determined by the attached claims togetherwith the equivalents thereof. The skilled persons will again appreciatethe fact that the explicitly disclosed embodiments were constructed forillustrative purposes only, and the scope will cover furtherembodiments, embodiment combinations, variations and equivalents thatbetter suit each particular use case of the invention. For example, inone alternative solution merely the support electronics, or a partthereof, and/or part of the emitters/detectors could be over-moulded bythe lightguide material. In that case the remaining emitters/detectorscould be located elsewhere, preferably still on the substrate, so thatthey are at least optically coupled to the over-moulded lightguide. Thecoupling could occur directly between the emitters/detectors and thelightguide (e.g. with a small gap or direct contact between theemitters/detectors and the lightguide), or via dedicated incouplingand/or outcoupling structures such as gratings.

The invention claimed is:
 1. A touchscreen arrangement, comprising: aflexible, optionally transparent, substrate film of plastics, thesubstrate comprising support electronics, or roll-to-roll processedprinted electronics including a number of printed conductors, forproviding power, control and/or communications connection to furtherelectronic components; a number of emitters and detectors arranged onthe substrate into contact with the support electronics, for emittingand detecting light, respectively; a lightguide layer of plastics moldedonto the substrate such that the emitters and detectors, and optionallyat least part of the support electronics, are substantially embedded inthe over-molded lightguide material of the lightguide layer, theproperties of the lightguide layer including the refractive index of thelightguide material being selected and the emitters and detectors beingconfigured so as to enable, when in use, total internal reflection (TIR)propagation of light within the lightguide layer between the emittersand detectors and recognition of a touch on the basis of a drop in theTIR performance as determined from the detected light, wherein thetouchscreen arrangement is adapted to recognize touch from a FTIR(frustrated TIR)-induced drop in the light intensity level as capturedby one or more detectors in contrast to an adaptively determined basicreception level, which is configured over time, optionally in intervalsor constantly, according to changes in the intensity of the lightdetected by the one or more detectors, during a TIR condition; and anon-deformable material layer directly upon the lightguide layerconfigured to adjust friction of a touch surface to enhance touch feelor change a slide of an actuation element thereon.
 2. The arrangement ofclaim 1, wherein the substrate includes a substrate portion providedwith a through hole.
 3. The arrangement of claim 1, wherein theconfiguration enables recognizing the touch, optionally locating thetouch and further optionally determining the touch pressure, from FTIR(frustrated TIR)-induced distribution as captured by one or moredetectors in contrast to a predetermined or adaptively determined basicdistribution during a TIR condition.
 4. The arrangement of claim 1,wherein the emitters include at least one LED (light emitting diode) orOLED (organic LED).
 5. The arrangement of claim 1, wherein the detectorsinclude at least one element selected from the group consisting of: aphotodiode, a phototransistor, and an image sensor.
 6. The arrangementof claim 1, wherein the lightguide layer includes at least one materialselected from the group consisting of: PC (polycarbonate), PA(polyamide, nylon), COC (cyclo olefin copolymer), COP (cyclo olefinpolymer), and PMMA (polymethyl methacrylate).
 7. The arrangement ofclaim 1, wherein the substrate includes at least one material selectedfrom the group consisting of: PET (polyethylene terephthalate), PC(polycarbonate), PEN (polyethylene naphthalate), PI (polyimide), LCP(liquid crystal polymer), PE (polyethylene), and PP (polypropylene). 8.The arrangement of claim 1, comprising a plurality of emitters anddetectors configured to sequentially activate and deactivate in groupssuch that in one group at least one emitter is associated with aplurality of detectors to increase the resolution in locating the touchrelative to the surface of the lightguide layer.
 9. An electronicapparatus comprising the arrangement of claim 1 and optionallycomprising a display or a touchpad associated with the arrangement,wherein the apparatus further optionally comprises one element selectedfrom the group consisting of: a mobile terminal, a personal digitalassistant, a music player, a multimedia player, a portable computer, adesktop computer, a palmtop computer, a portable radio, and a controldevice for an industrial application.
 10. The arrangement of claim 1,further comprising a blocking structure configured to block a zero-orderpath between an emitter and a corresponding detector to increase therelative proportion of TIR-propagated, internally reflected, light atthe detector.
 11. The arrangement of claim 9, further comprising ablocking structure configured to block a zero-order path between anemitter and a corresponding detector to increase the relative proportionof TIR-propagated, internally reflected, light at the detector.
 12. Amethod for manufacturing a touchscreen arrangement, comprising:providing a flexible substrate film of plastics, which is optionallyoptically substantially transparent, the substrate defining a throughhole in a portion of the touchscreen arrangement adapted to recognizetouch from a frustrated total internal reflection; arranging supportelectronics, such as printed electronics including a number of printedconductors, on the substrate for providing power, control and/orcommunications connection to further electronic components; arranging anumber of emitters and detectors on the substrate into contact with thesupport electronics, for emitting and detecting light, respectively;producing a lightguide layer of plastics onto the substrate throughinjection molding using the substrate carrying the emitters, detectorsand support electronics as an in-mold insert such that the emitters anddetectors, and optionally at least part of the support electronics, aresubstantially immersed in the over-molded lightguide material of thelayer, the properties of the lightguide layer including the refractiveindex of the lightguide material being selected and the emitters anddetectors being configured so as to enable, when in use, total internalreflection (TIR)-type propagation of light within the lightguide layerbetween the emitters and detectors and recognition of a touch on thebasis of a drop in the TIR performance as determined from the detectedlight, wherein the touchscreen arrangement is adapted to recognize touchfrom a FTIR (frustrated TIR)-induced drop in the light intensity levelas captured by one or more detectors in contrast to an adaptivelydetermined basic reception level, which is configured over time,optionally in intervals or constantly, according to changes in theintensity of the light detected by the one or more detectors, during aTIR condition; and producing a material layer directly upon thelightguide layer configured to adjust friction of a touch surface toenhance touch feel or change a slide of an actuation element thereon.13. The method of claim 12, wherein roll-to-roll manufacturing isutilized for producing the substrate or providing the substrate with atleast some of the support electronics, emitters, or detectors, or forproviding the substrate with the lightguide layer or some otherfunctional layer.
 14. The apparatus of claim 12, further comprising ablocking structure configured to block a zero-order path between anemitter and a corresponding detector to increase the relative proportionof TIR-propagated, internally reflected, light at the detector.
 15. Anarrangement for a touchscreen, comprising: a flexible, optionallytransparent, substrate film of plastics, the substrate comprisingsupport electronics, or roll-to-roll processed printed electronicsincluding a number of printed conductors, for providing power, controland/or communications connection to further electronic components; anumber of emitters and detectors arranged on the substrate into contactwith the support electronics, for emitting and detecting light,respectively; and a lightguide layer of plastics molded onto thesubstrate such that the emitters and detectors, and optionally at leastpart of the support electronics, are substantially embedded in theover-molded lightguide material of the layer, the properties of thelightguide layer including the refractive index of the lightguidematerial being selected and the emitters and detectors being configuredso as to enable, when in use, total internal reflection (TIR)propagation of light within the lightguide layer between the emittersand detectors and recognition of a touch on the basis of a drop in theTIR performance as determined from the detected light, wherein thetouchscreen arrangement is adapted to recognize touch from a FTIR(frustrated TIR)-induced drop in the light intensity level as capturedby one or more detectors in contrast to an adaptively determined basicreception level, which is configured over time, optionally in intervalsor constantly, according to changes in the intensity of the lightdetected by the one or more detectors, during a TIR condition, thearrangement further comprising an additional non-deformable materiallayer directly upon the lightguide layer configured to adjust frictionof a touch surface to enhance touch feel or change a slide of anactuation element, optionally a finger, thereon.
 16. The arrangement ofclaim 15, wherein the substrate includes a substrate portion providedwith a through hole.
 17. The arrangement of claim 15, wherein theconfiguration enables recognizing the touch, optionally locating thetouch and further optionally determining the touch pressure, from FTIR(frustrated TIR)-induced distribution as captured by one or moredetectors in contrast to a predetermined or adaptively determined basicdistribution during a TIR condition.
 18. The arrangement of claim 15,wherein the emitters include at least one LED (light emitting diode) orOLED (organic LED).
 19. The arrangement of claim 15, wherein thedetectors include at least one element selected from the groupconsisting of: a photodiode, a phototransistor, and an image sensor. 20.The arrangement of claim 15, wherein the lightguide layer includes atleast one material selected from the group consisting of: PC(polycarbonate), PA (polyamide, nylon), COC (cyclo olefin copolymer),COP (cyclo olefin polymer), and PMMA (polymethyl methacrylate).
 21. Thearrangement of claim 15, wherein the substrate includes at least onematerial selected from the group consisting of: PET (polyethyleneterephthalate), PC (polycarbonate), PEN (polyethylene naphthalate), PI(polyimide), LCP (liquid crystal polymer), PE (polyethylene), and PP(polypropylene).
 22. An arrangement for a touchscreen, comprising: aflexible, optionally transparent, substrate film of plastics, thesubstrate comprising support electronics, or roll-to-roll processedprinted electronics including a number of printed conductors, forproviding power, control and/or communications connection to furtherelectronic components; a number of emitters and detectors arranged onthe substrate into contact with the support electronics, for emittingand detecting light, respectively; a lightguide of plastics molded ontothe substrate such that the emitters and detectors, and optionally atleast part of the support electronics, are substantially embedded in theover-molded lightguide material, the properties of the lightguideincluding the refractive index of the lightguide material being selectedand the emitters and detectors being configured so as to enable, when inuse, total internal reflection (TIR) propagation of light within thelightguide between the emitters and detectors and recognition of a touchon the basis of a drop in the TIR performance as determined from thedetected light, wherein the touchscreen arrangement is adapted torecognize touch from a FTIR (frustrated TIR)-induced drop in the lightintensity level as captured by one or more detectors in contrast to anadaptively determined basic reception level, which is configured overtime, optionally in intervals or constantly, according to changes in theintensity of the light detected by the one or more detectors, during aTIR condition, the substrate defining a through hole positioned withinan area of the touchscreen arrangement adapted to recognize touch from aFTIR, wherein the number of emitters and detectors comprise a pluralityof emitters and detectors configured to sequentially activate anddeactivate in groups such that in each group at least one emitter isassociated with multiple adjacent detectors to increase the resolutionin locating the touch relative to the surface of the lightguide, atleast some of the detectors of the plurality being associated with aplurality of emitters so that the groups overlap relative to thedetectors; and a material layer directly upon the lightguide layerconfigured to adjust friction of the touch surface to enhance touch feelor change a slide of an actuation element thereon.
 23. The method ofclaim 22, further comprising providing a blocking structure configuredto block a zero-order path between an emitter and a correspondingdetector to increase the relative proportion of TIR-propagated,internally reflected, light at the detector.